I was using a 4k7 pullup (with TTL load) on port 0 and had no clue as to why i was using 4k7. Also to light a bicolor LED via port0 i was using a 1k pullup (Trial and error method of determination used here!!) So i was trying to figure out a logical method to calculate the pull up.
1) For LEDs do not use pullups, insert the LEds to be lit with pulldown, this allow you a bit more current for the LED.
2) The 'method to calculate the pull up' is so involved that unless power consumption (or heat) is a major concern, I would just go by my 'rule of thumb' mentioned in my previous post.

Erik